CNC Circuit Mill/Manufacturing Instructions/Upload Microcontroller Code
- USB Cable
- Arduino Microcontroller
-  Wires, 10cm long, 22AWG, 1cm stripped both ends
- Arduino Integrated Development Environment
[RAW INFO - TO BE ORGANIZED]
Okay, I was new at this when I did it (and it was before I started documenting so very carefully) so try this. If there's anything missing I'll have to snag a new Uno and walk myself back through it again. On the MTM Snap electronics page http://mtm.cba.mit.edu/machines/mtm_snap-lock/build/software.html
The Makefile is currently setup for an Uno on Mac OS X. If you're using another operating system, you'll need to replace /dev/tty.usb* with the serial port of your Arduino. (On Linux, this is likely /dev/ttyACM0 for an Uno and /dev/ttyUSB0 for other boards. On Windows, look in the Device Manager to determine the COM port.) If you're using an Arduino Duemilanove, you'll need to change the baud rate from 115200 to 57600.
So, first make sure that you've got make installed. I'm assuming that you all are using an open OS like Ubuntu, so use one of those specified COM ports. (I was using an Arduino Uno so my COM port was the specified ttyACM0) So you download the grbl files, open the makefile in whatever text editor you're using, and fix the /dev/tty statement to whatever it should be for your system. It's in that first block of text in the makefile after all the introductory comments, and the line starts with "Programmer".
So after you fixed the COM port in the makefile, you open a terminal, go to the grbl folder in the directory where the grbl was downloaded (probably your Downloads folder), and type in the "make clean" and "make" commands to compile it, and then (make sure your Arduino is connected) type the "make flash" command. That should make the Arduino light up and flash as usual as the grbl sketch uploads. As I said before, if that doesn't work let me know and I'll walk through with a fresh arduino and make sure I didn't leave anything out. I'm not a make guru by any means, so be patient.
After uploading I didn't bother with the terminal anymore. I opened up the Arduino IDE and opened the serial terminal under "Tools." It should open and populate with something like "GRBL 6.0 type $ for dump" I can't remember exactly what it says, but that's the essence of it. That shows you that grbl is installed on the board and that it's now editable. So you can type $ and see all the current settings, and change them according to this page:
You need to do the math for your leadscrews to get your steps/mm.